Molded plastic lever key for locking or non-locking operation



Jam 5, 1965 A. M. BLACKALLER 3,164,687

MOLDED PLASTIC LEVER KEY FOR LOCKING OR NON-LOCKING OPERATION Filed April 18, 1961 INVENTOR. Arf/)ur M Bloc/aller if/W United States Patent O 3,164,687 MGEIDED PLASTIC LEVER KEY FOR LOCKING OR NON-LOCKING OPERATION Arthur M. Blaelkaller, Chicago, Ill., assignor to Automatic Electric Laboratories, Ine., Northlake, Ill., a corporation of Delaware Filed Apr. 18, 1961, Ser. No. 103,746 1 Claim. (Cl. 20d- 1) This invention relates to switching mechanisms, and more particularly to lever key switches such as those commonly used, for example, on a telephone operators switchboard. It is directed particularly to the construction of the lever key itself.

The present application is an improvement over the copending patent application Serial No. 101,155, filed on April 6, 1961, by V. L. Vander Kooy and assigned to the present assignee. In the present case, the lever key which is formed of one piece and is preferably molded of plastic material, has a lower cam member designed for locking or non-locking operation.

It is therefore a primary feature of this invention to provide a lever key of the general type disclosed in the aforementioned Vander Kooy application, for mounting beneath an escutcheon plate, with the lower end having shoulders which serve as stops for the lever, but with only one of these shoulders designed to lock the lever in the opera-ted position until it is manually released, while the other shoulder is designed for non-locking operation. This permits a change from locking to non-locking operation by merely rotating the lever key 360 in the mounting frame.

The invention will be more fully understood from the following detailed description of an embodiment thereof. In the accompanying drawings:

FIG. l is a front view of a lever key switch in the normal position, showing the top of the armature springs, the mounting for the lever key, and the edge of the escutcheon plate.

FIG. 2 is a side view of the switch with the lever key mounting remo-ved, showing the lever key in the normal position with the armature springs resting against the lower portion of the lever key. The spring pileups are visible, and the armature springs have flattened sections at the ends which engage the lever key.

FIG. 3 is a side view of the lever key showing the lever key in an extreme position with one shoulder against the escutcheon plate and the lower portion pressing outwardly on one armature spring.

FIG. 4 is an exploded perspective view of the lever key and its mounting arms showing the overall shape of the cam face, and the relative size of the locking and nonlocking shoulders.

Referring now to the drawings, in FIGURES 1, 2, 3 and 4 the lever key 3d is of the general type disclosed in the aforementioned Vander Kooy application and according to the preferred embodiment is used with escutcheon plate 2i), framework 40 and spring sets 50. The escutcheon includes apertures 21 which are aligned with corresponding apertures 42 of the framework to provide for screws 22 which are the means to secure the escutcheon to the framework. In a similar manner spring sets l) are secured to the framework by means of screws 53. Spring 51 of each set includes a flat end portion SZ which engages or rides against cam surface 31 of the lever key. Thus spring 51 serves as an armature Spring and transmits the motion of the lever key to the spring sets.

The lever key is molded and preferably made of insulating material such as a plastic. It features a thin semicircular shaped shank or upper portion 37 and a lower portion 36 which is of greater thickness. At the 3,164,687 Patented Jan. 5, 1965 lCC- center of the upper portion and extending therefrom is a threaded portion 38 which projects through slot Z3 of the escutcheon and receives handle 55.

0n the lower end of the thicker portion is a cam surface 31 engaging flat end portion 52 of armature springs 51. At the upper side and projecting as embosses on opposite sides of shank 37 are .two pairs of asymmetrically shaped cam surfaces 34 and 35 which engage the bottom surface of the escutcheon plate, and stops the lever key so it is either in a locking or non-locking position depending on which direction the handle is moved. In addition cam surfaces 3d and 3S terminate in corresponding arcuate sides 32 and 33 which flow into cam surface 31 to thereby dene the periphery of the lower portion.

Cam surface 3S is at a different angular and space relationship to the pivot point than cam surface 34 and, consequently the former enables the lever key to advance or ride further up on flat portion 52 than does cam surface 34. The difference accounts for the aforementioned locking of the lever key when moved in one direction and non-locking when moved in another direction.

Between cam surfaces 3d and 35 and cam surface 31 is an aperture wherein shaft 66 is positioned. The shaft is supported by corresponding apertures 41 of the framework.

It should be appreciated that which set of springs is associated with the locking side of the lever key is arbitrary and depends on how the lever key is positioned in the framework, A change can he made merely by rotating the lever key 360 with respect to the framework.

Handle 55 is deflected manually in either of two directions. As viewed in FIGURES 2 and 3 of the drawing lthe lever key locks into position when handle 55 is moved to the right, and when moved to the left it is nonlocking as the flat portion 52 urges the lever key to its neutral position. In the locking position the line of force between the carne surface and flat portion 52 is directed through the pivot point. In the non-locking position the line of force does not go through the pivot point and thus does not lock.

While I have described the above principles of my invention in connection with a specific embodiment, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope and spirit of my invention as hereinafter claimed.

What is claimed is:

In a lever key switch, an escutcheon plate having a slot therein, a framework secured to and depending from said plate, a molded lever key, two switching springs mounted on said frame on opposite sides thereof and each having .a flat end portion, said key having integrally molded therewith a thin at upper shank portion extending upward through said slot and including a threaded portion to which a handle may be attached, and having a lower portion of greater thickness than said upper portion, a pin extending through said lower portion for pivotally mounting said key in said frame, said lower portion forming a first cam surface at the lower end thereof for engaging said flat end portions of said switching springs thereby to actuate the corresponding spring, and forming at the upper end thereof second and third cam surfaces on opposite sides of said pin to stop the pivoting Imovement of said pin, said second and third cam surfaces being asymmetrical to each other and being respectively located in relation to said pin so as to enable said key, when rotated in one direction to permit said first cam sur-face to move along the corresponding flat portion sufciently to reach a locking position where the force of said flat end portion against said rst cam surface is directed substantially through said pin, and, when rotated in the other direction, to restrict the movement of said rst cam surface to Where the corresponding at portion urges said key back to its neutral position.

References Cited in the le of this patent 4 v Gary et al Dec. 16, 193 Little Dec. 26, 1939 Stehlik July 21, 1942 Mossman Seplt. 23, 1952 Weld Mar. 3, 1953 Dubeau June 28, 1960 

